Avaliação quali-quantitativa do percolado gerado no aterro controlado de Santa Maria - RS

• Autor(a) principal: Gomes, Tiago Luis
• Data de Publicação: 2005
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Manancial - Repositório Digital da UFSM
• dARK ID: ark:/26339/00130000168ms
• Texto Completo: http://repositorio.ufsm.br/handle/1/7670
• topic: Resíduos urbanos; Aterro controlado; Percolado; Balanço hídrico; DBO e DQO; Urban wastes; Landfill; Leachate; Balance water; BOD and COD; CNPQ::ENGENHARIAS::ENGENHARIA CIVIL

The subject of greater concern related to environmental degradation in a disposal system of urban solid wastes is the leachate generation. The high pollutant power of leachate is due to the presence of organic and inorganic composts formed during the decomposition of wastes. The inadequate leachate management can pollute environmental sites, particularly the soil, surface waters and groundwater basin. Through the verification of a system of treatment conducted by stabilization ponds it is possible to evaluate the efficiency of the process responsible for the removal of pollutants and to esteem the impact generated by the outflow in a receptor. This evaluation aimed to study the environmental impact generated in Caturrita's Landfill, located in Santa Maria RS, which has a total area of 374435.72 m2 and is part of the hidrographic Sub basin of Arroio Ferreira, receiving approximately 150 ton/day of urban solid wastes. Through Swiss, Rational and Balance Water Methods, leachate flows were estimated and checked by real measurements which took place on the site, thus determining the methodology employed in the quantitative evaluation of the leachate which was generated. The qualitative evaluation consisted of a monitoring system that was conducted from August 2003 to March 2005. It presented characteristics of the leachate generated during the disposal of solid wastes, as well as characteristics of the quality of water in the outflow receptor of the system of treatment of leachate. This evaluation enabled the determination of the effectiveness concerning the system of ponds used for stabilization, together with the determination of the outflow impact and the present degradation status of the landfill. The quantitative results were obtained through the use of error graphs evaluation for long series (data gathered from 34 years of precipitation and 29 years of evapotranspiration) and short series (between May 2004 and April 2005 for precipitation and evapotranspiration) and presented for the Balance Water, Rational and Swiss Methods, 31%, 13% and 34% of error rate, considering long historic series of data; and 48%, 21% and 76%, considering short historic series of data. Regarding the qualitative aspects of leachate, more precisely its degradation status (solid waste degradation), showing a confidence level of 95%, the mean ratio found between BOD/COD was 0.46± 0.08 and concerning the PH it was 7.9 ± 0.14. The mean effectiveness of the system of treatment was 69±11% when BOD was removed and 58±10% when COD was removed. In 92 % of the cases, the outflow presented BOD values above the maximum limit of 200 mg/L. A similar situation is observed regarding the COD parameter, presenting a maximum limit of 450 mg/L. The Balance Water Method proved to be apt to be used in dimensioning processes of systems of treatment of outflows, showing a mean error of 34% above the real flow and was susceptible to the real montly tendencies. The degradation processes of leachate in Caturrita's Landfill were found in the end of the final acidogenic phase, due to the values found for the ratio BOD/COD and the PH, enphasizing how much organic matter is still possible to be degraded. The mean effectiveness of the system of ponds of treatment was showed to be insufficient, considering that the mean concentration on the site is 390± 91mg/L (outflow site) for the first and 1403±209 mg/L (outflow site) for the second. In order to meet the values indicated by law (Portaria 05/89 SSMA RS), it would be necessary a concentration inferior to 200 mg/L for BOD and 450 mg/L for COD.